As the DxOMark Camera Sensor Ratings for the K-5 IIs are so similar to the K-5 II already reviewed (where we compared scores to its semi-pro market rivals) for this K-5 IIs review comparisons with professional cameras adds more perspective.

The obvious comparison is to the only other DSLR without an anti-aliasing filter, the £2390 36Mpix full-frame Nikon D800E, costing around £1450 more than the 16Mpix Pentax K-5 IIs with its APS-C sensor.

DxOMark Sensor Measurements indicate the pixel quality of these two cameras is very similar, illustrated by the results recorded in Screen Mode. Differences in image quality are more pronounced however when examining DxOMark Measurements in Print Mode due to the larger full-frame sensor utilized by the D800E.

The graph for Color Sensitivity shows how results for the K-5 IIs and D800E are very similar in Screen mode and this trend continued for all measurements. It was only examining Print Measurements that differences appeared.

Drilling down into the Landscape Score (Dynamic Range) at base ISO sensitivities the scores are also very similar, 14.33 Ev for the D800E and 14.14 Ev for the K-5 IIs. For landscape work at the base sensitivity the K-5 IIs is virtually as good as the D800E in terms of Dynamic Range. It’s only as you increase ISO sensitivity where the D800E pulls ahead and at the Measured ISO1600 result the difference is at its most pronounced with the D800E displaying around a ½ stop improvement over the K-5 IIs. Remember this only considers Dynamic Range however and doesn’t take account of the advantages the greater resolution and full-frame sensor of the D800E offers for landscape photography.

Looking at Color Sensitivity the same pattern doesn’t continue however where the D800E out performs the K-5 IIs at all ISO sensitivities and records rich color with the sensor sensitivity set roughly 1-stop higher than the K-5 IIs. This remains true up to ISO 3200 where the difference narrows due to the Pentax high ISO ‘smoothing’ that reduces noise in all images including RAW files. In-camera ‘smoothing’ (even of RAW files) reduces image sharpness however and can lead to the complete loss of fine detail (For further information on Pentax high ISO noise smoothing, see our DxOMark review for Pentax cameras). Regardless this image processing for studio or portrait photographers the D800E renders better Color Depth for richer and more nuanced color.

The most pronounced difference appears when we look at the SNR18% chart and the Sports (Low-Light ISO) ratings. The D800E hits 2-stops better low-light performance than the K-5 IIs recording pictures without significant quality loss at ISO 3200, the K-5 IIs only manages this up to ISO 800. Despite the fact pixel quality between the two cameras is very similar the larger full frame sensor of the D800E catches more light and, as a result, less noise. The significantly higher resolution of the D800E, 36Mpix compared to the K5 IIs 16Mpix, also in theory results in sharper resolution from the D800E.

So the K-5 IIs doesn’t quite live up to the benchmarks set by the D800E but how does it fare against other notable full-frame models like the Nikon D600 and Canon 5D MKIII that although often classed as ‘affordable’ still cost significantly more than the K-5 IIs? Well with an overall score of 94 the 24Mpix Nikon D600 remains well out in front achieving the best results in all categories and with the highest resolution of the three models to boot. The K-5 IIs does nudge the 5D MKIII into 3rd however with an overall score of 82 compared to 81.

Examining the Portrait (Colour Depth) ratings more closely indicates little difference between the K-5 IIs and 5D MKIII with 23.9 bits compared to 24 bits respectively. So it’s left to the Landscape and Sports categories for the pros and cons of these models to become apparent. Significantly trumping the 5D MKIII with a Landscape rating of 14.1 Ev the K-5 IIs records a massive 2.4 Ev greater Dynamic Range than the Canon and it’s worth repeating that rating puts it a 4th out of all cameras for Dynamic Range.

If low-light performance is more important though the full-frame 5D MKIII’s Sports Score of 2293 ISO compared to 1208 ISO on the K-5 IIs gives it the edge. In real terms it means the 5D MKII captures acceptable pictures with the sensor set roughly 1-stop more sensitive than the K-5 IIs can be and as a result the Canon lends itself better to the often low-light environments of press or wedding work.

Overall therefore the D600 is way out in front but its horses for courses choosing between the K-5 IIs and the 5D MKII depending on what you’re going to shoot. With a very similar DxOMark Overall Score between the two but a better Low-light ISO rating the 5D MKIII is the more versatile camera but it can’t get anywhere close to the dizzying heights the K-5 IIs sets for Dynamic Range.

Further readings for the Pentax K-5 IIs maintains the excellence of its sister model the K-5 II

To provide photographers with a broader perspective about mobiles, lenses and cameras, here are links to articles, reviews, and analyses of photographic equipment produced by DxOMark, renown websites, magazines or blogs.